Labels can be permanent or repositionable; once applied, numbers & letters are there to stay - unless you want to change them. Made of B-498 plastic coated cloth with pressure sensitive adhesive that sticks to any clean, dry surface. Choose from 5 different sizes. Markers contain numerical or alphabetical sequences on the same card. Smaller marker sizes contain complete sequence; larger markers break the alphabet into three parts: A-J, K-T and U-Z. Color is black on yellow.